Recent Advances of Oxygen Carriers for Hydrogen Production via Chemical Looping Water-Splitting

Abstract

Hydrogen is an important green energy source and chemical raw material for various industrial processes. At present, the major technique of hydrogen production is steam methane reforming (SMR), which suffers from high energy penalties and enormous CO2 emissions. As an alternative, chemical looping water-splitting (CLWS) technology represents an energy-efficient and environmentally friendly method for hydrogen production. The key to CLWS lies in the selection of suitable oxygen carriers (OCs) that hold outstanding sintering resistance, structural reversibility, and capability to release lattice oxygen and deoxygenate the steam for hydrogen generation. Described herein are the recent advances in designing OCs, including simple metal oxides (e.g., Fe, Zn, Ce, and Ti-based metal oxides) and composite metal oxides (e.g., perovskite, spinel, and garnets), for different CLWS processes with emphasis on the crucial parameters that determine their redox performance and future challenges.

The potentials of boron-doped (nitrogen deficient) and nitrogen-doped (boron deficient) BNNT photocatalysts for decontamination of pollutants from water bodies

“…Furthermore, in the water splitting technique, the energy must be in the range of 2.2 eV to 2.8 eV and this exceeds the free energy of water splitting (1.23 eV). 19 In this work, we first analyze the electronic band structure of the pristine SWBNNT semiconductor, and the results are shown in Fig. 4(a) .…”

Introduction and Advancements in Room Temperature Ferromagnetic Metal Oxide Semiconductors for Enhanced Photocatalytic Performance

“…Unraveling Mechanistic Insights: Researchers delve into the mechanics that underpin visible light photocatalysis, delving into the intricacies of bandgap engineering, energy level alignment, and charge carrier dynamics [110][111][112]. These insights illuminate the avenues for optimizing the performance of photocatalytic materials.…”

Improvement of Process Conditions for H2 Production by Chemical Looping Reforming

“…The selection of a proper oxygen carrier is essential to ensure selectivity towards partial oxidation to syngas rather than complete combustion [28]. Furthermore, an ideal oxygen carrier should be economically competitive while at the same time ensuring stable productivity and structural stability across several repeated looping cycles, without loss in selectivity and yields due to the sintering or poisoning of the carrier, particularly due to coking [29].…”